<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>background-size</title>
	<style type="text/css">

		/*可以用来做适配*/
		.box{
			width: 400px;
			height: 400px;
			border: 1px solid #000;
			margin: 50px auto 0;
			background: url(../images/apple.png) no-repeat;

			/*强制把背景图放大*/
			background-size: 500px 500px;
		}

		.box{
			width: 400px;
			height: 400px;
			border: 1px solid #000;
			margin: 50px auto 0;
			background: url(../images/apple.png) no-repeat;

			/*强制把背景图放大*/
			background-size: cover;
		}
	</style>
</head>
<body>
	<div class="box"></div>
	<div class="box2"></div>
</body>
</html>